Learn new things.  It helps to build  confidence . It keeps you happy.  And it is fun being a student again knowing that this time you will definitely do better. 
You could try your hand in anything as long as it makes you happy.  And remember there is no age limit to learning.
Sometimes a particular skill could not be learnt owing to financial strain or merely due to lack of time.  It can surely be pursued again if you make some time for yourself.

It is imperative that you make the time for yourself.  Because you are important and worth it. Don’t let go of the idea for something  that is not the source of your happiness.  Sometimes you need to be selfish to gain happiness.  As long as you are not causing harm to anyone, go ahead and pursue your dreams.  The Universe is standing with its arms open to draw you in, so rush towards it to be immersed in new knowledge.  It will never go in vain.Knowledge broadens your perspective.  There is no limit to knowledge unless you want to end it. It’s upto you to pursue further and the more you know the better .